A metal structure of the generic type for the backrest of a vehicle seat is disclosed in WO 00/47441 A1. It comprises an integrally pressed rear shell having an inner surface area which is provided with openings and from which a rectangular bent flange extends forwards at the edge, together with an integrally pressed front shell having an inner surface area, which at the edge has a bent flange extending rearwards at right angles. Punched openings are provided in the inner surface area of the front shell, in such a way that the remaining areas of sheet metal have a corrugated spring structure. The front and rear shells have substantially the same wall thickness throughout and in the area of the overlapping bent flanges are connected together by spot-welding. The outer side of the body produced in this way is then partially covered with polyurethane foam.
In the area for attachment of the seat back rake adjusters (recliner) the lateral faces of the rear shell are provided with U-shaped beads. The fixing lugs of the seat back rake adjusters are inserted and bolted into these channel-like depressions. The fixing lugs on the backrest side are later completely hidden by the fitted front shell.
The metal structure of the seat part may also have the same construction.
This production concept is basically suited to the manufacture of high-quality vehicle seats. Since force is introduced from the fixing lugs into the body solely by of the rear shell, the latter is produced from a sheet metal of relatively large wall thickness. The weight of the metal structure is accordingly high.